1. Technical Field
The present invention relates to a lens array substrate on which a lens is formed, an electro-optical apparatus which is provided with the lens array substrate, and electronic equipment which is provided with the electro-optical apparatus.
2. Related Art
In a display area of an electro-optical apparatus (a liquid crystal device) which is used as a light valve of a projector, a plurality of pixels are disposed in a matrix shape, and in the pixel, only the light which reaches a translucent area (a pixel opening area) surrounded by a wiring or the like is imparted to display. Here, a configuration such that light from a lighting source is converged to a translucent area by configuring the electro-optical apparatus with a lens array substrate as a counter substrate has been proposed. In addition, as the lens array substrate, a configuration has been proposed such that after a first lens surface which is formed of a concave surface is formed on one side of a substrate surface of a translucent substrate, the substrate surface is covered by the first translucent lens layer which has a refractive index different from that of the translucent substrate, and then the concave surface on which the first lens surface is reflected is used as a second lens surface for the surface opposite to the side of the translucent substrate in the first lens layer (refer to JP-A-2013-57781).
Further, in the configuration disclosed in JP-A-2013-57781, a translucent protective layer is stacked on the surface opposite to the side of the translucent substrate with respect to the second lens layer that covers the second lens surface.
In the lens array substrate, it is preferable to provide an optical path length adjusting layer (a translucent layer) having a predetermined thickness on the emission side with respect to the lens in order to properly control a position in which the light emitted from a lens is converged; however, the optical path length adjusting layer (the translucent layer) having a sufficient thickness is not provided in the lens array substrate disclosed in JPA-2013-57781. For example, in the lens array substrate disclosed in JP-A-2013-57781, the protective layer having a small thickness is directly stacked with respect to the second lens layer that covers the second lens surface. In addition, in the lens array substrate disclosed in JP-A-2013-57781, since the concave surface on which the first lens surface is reflected is used as the second lens surface for the surface opposite to the side of the translucent substrate in the first lens layer, it is difficult to provide the optical path length adjusting layer (the translucent layer) having the sufficient thickness with respect to the first lens surface.
Accordingly, in a case where a two-stage is provided, it is preferable to form a first lens array by forming the first lens layer which is formed of a silicon oxinitride film, and a first translucent layer (the optical path length adjusting layer) which is formed of a silicon oxide film, after forming the first lens surface which is formed of the concave surface on one substrate surface of the translucent substrate formed of a quartz substrate or the like. Further, it is preferable to form a second lens array by forming a second lens layer which is formed of the silicon oxinitride film on the side opposite to the translucent substrate with respect to the first translucent layer, forming a second lens surface which is formed of a convex surface on the surface opposite to the side of the translucent substrate of the second lens layer, and then forming a second translucent layer (the optical path length adjusting layer) which is formed of the silicon oxide film.
However, in the above-described configuration, there is a problem in that a reflection is generated on an interface between the first lens layer which is formed of the silicon oxinitride film and the first translucent layer which is formed of the silicon oxide film, or an interface between the first translucent layer which is formed of the silicon oxide film and the second lens layer which is formed of the silicon oxinitride film, and therefore, it is likely that an amount of light contributing to a display will be reduced.
On the other hand, in a case where a single stage lens is provided, after forming the lens surface which is formed of the concave surface on one substrate surface of the translucent substrate formed of a quartz substrate or the like, for example, the lens layer which is formed of the silicon oxinitride film, the translucent layer (the optical path length adjusting layer) which is formed of the silicon oxide film, the protective layer, and a translucent electrode which is formed of an ITO film are formed in order. However, also in the above-described configuration, reflection is generated on an interface between the lens layer which is formed of the silicon oxinitride film and the translucent layer which is formed of the silicon oxide film, and therefore, it is likely that the amount of the light contributing to the display will be reduced.